The Dragon Ball Z Theory That Connects Dr. Gero To Goku's Mysterious Virus
In the first half of Akira Toriyama's "Dragon Ball Z," it took flashy Ki transformations and a well-placed Spirit Bomb to tackle planet-destroying foes such as Vegeta and Frieza. The list of deadly combatants has only become much more dangerous in the "Super" era of the series. Characters like Hit, Jiren, and a canon Broly have more than earned their recognition as some of the most powerful Dragon Ball characters. Although often overlooked in favor of other obvious powerhouses, one enemy's actions during "Dragon Ball Z" definitely came uncomfortably close to dooming Goku and the rest of the Z Warriors.
Dr. Gero makes his debut during the "Android Saga," but his appearance is slightly abrupt due to Android 17 and 18 betraying him. Still, his shadow looms even in death. The Androids have killed the Z Fighters in Trunks' timeline. By the end of "The Cell Saga," Goku is dead after sacrificing his life, and his son Gohan is the one who saves the day. Dr. Gero can be blamed for the headaches Goku and the gang have to deal with during these sagas. His creations cause all of this tragedy. But at least he didn't develop the random and mysterious virus that almost takes Goku out during the "Android Saga." Or does Dr. Gero deserve credit for that one too? One "Dragon Ball Z" theory among fans certainly thinks so.
Some fans believe Dr. Gero created the virus
In the "Dragon Ball Z" manga chapter 141 (via Viz), Trunks appears from the future and warns Goku about the horrible fate that will befall his friends because of Gero's Androids. But the most shocking revelation from their conversation is that Goku doesn't even get to battle with his comrades, as a virus attacks his heart and kills him. Trunks, of course, gives Goku an antidote, as the future has finally developed a cure for it. But we never learn where the virus came from or how Goku contracted it. Fans on the DBZ Reddit have come up with a few theories, with one plausible option being that Dr. Gero created the virus.
"The heart virus was an early attempt at Dr. Gero assassinating Goku," u/andorinter posted. "Gero created an airborne virus which his monitoring drones dispersed all across the earth. Many people carried the virus, but it was only lethal to Goku." Some fans defended the theory as a solid explanation for a glaring plot hole, and honestly, it does line up nicely with a few other facts. For one, in the episode "A Handy Trick" (via Crunchyroll), Dr. Gero takes a page from the "Villain 101" playbook and details how he's kept track of Goku over the years. He used little robotic bugs to keep tabs on Goku, from his childhood to his battle with Vegeta. It's not outlandish to think that Dr. Gero would have created the virus and used the little bugs as a means to spread it during this surveillance.
Other theories point to Goku's otherworldly travels
Dr. Gero being the master manipulator behind the heart virus is a neat theory, but it's not the only one. Another popular scenario of the virus' possible origins is linked to Goku's space adventures before the events of "The Android Saga." Specifically, Goku spends significant time battling Frieza on Namek and then recuperating on the planet Yardrat. The hero never showed any virus symptoms before traveling to the two worlds. So it's awfully suspicious that the Saiyan comes down with a virus strong enough to attack his alien bloodline after his galactic travels. Some fans couldn't help but notice this as well.
The Namek/Yardrat theory pops up as a consistent one on the Dragon Ball Wiki Forum. And as Redditor u/diamondtoss best said, "Fighting aliens and visiting alien planets is sure to expose you to different diseases." The only weakness the theory has compared to Dr. Gero's possible involvement is that if the virus was alien-born, then how exactly was Trunks' timeline able to come up with a cure? The antidote's creation on Earth would suggest that other people on the planet were eventually tested. And thus, after a while, a way to finally beat the virus was created. Or maybe this means that Goku was patient zero. Perhaps, one day Toriyama will reveal the virus' true origins.